Browsing by Author "Knepp, Michael Matthew"
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- Cardiovascular Activity During Laboratory Tasks in Individuals with High and Low WorryKnepp, Michael Matthew (Virginia Tech, 2007-05-09)Anxiety and worry have been related to exaggerated cardiovascular reactivity and delayed recovery to laboratory stressors, and to increased risk of cardiovascular disease. This study examined cardiovascular responses in high and low worriers to a range of laboratory tasks. The aim of this study was to determine if there is a task-specific relationship between worry and aberrant cardiovascular responding. Forty-one undergraduate women were recruited online to form low and high worry groups by use of the Penn State Worry Questionnaire. Four common laboratory tasks and two conditions designed to elicit worry and relaxation were used: hand cold pressor, mental arithmetic, orthostatic position, supine position, worry imagery, and relaxation imagery. Heart rate, heart rate variability, impedance cardiography, and blood pressure indices were collected to assess task reactivity and recovery, particularly in relation to autonomic nervous system activity. The high worry group had significantly higher heart rates throughout the study. The low worry group presented increased cardiovascular recovery to various tasks. The high worry group during task and post-task periods also increased parasympathetic withdrawal and sympathetic activation. The results of the study suggest that high worriers have decreased vagal control of the heart. The implications of this study suggest a potential link between the post-task period in high worriers and cardiovascular disease. Further research is recommended.
- Cardiovascular Reactivity to and Recovery from Laboratory Tasks in Low and High Worry WomenKnepp, Michael Matthew (Virginia Tech, 2010-03-23)Anxiety and its cognitive component of worry have been related to exaggerated cardiovascular reactivity and delayed recovery to laboratory stressors, and to increased risk of cardiovascular disease. Previous research on the anxiety-cardiovascular system relationship, including data from Knepp and Friedman (2008), are included to support this project. Two experiments were completed during the course of this study. The first consisted of two peripheral-based body positioning tasks. The second experiment used an active versus passive sympathetic stress task paradigm (mental arithmetic, hand cold pressor). Subjects were nonsmokers free of cardiovascular and neurological disease. Trait worry was examined through the Penn State Worry Questionnaire (PSWQ). Blood pressure recordings and cardiac recordings through ECG and ICG were done in each experiment during seven epochs: an anticipatory baseline with three baselines preceding and three recovery periods following each task. Repeated measures analysis was run on all cardiovascular measures. In the first experiment, high worriers had worsened blood pressure reactivity to task. The second experiment found that high worriers had increased stroke volume across all epochs. There were mixed findings in the studies relating to subjects acclimated to the laboratory experience. Future directions of research relating anxiety, worry, and cardiovascular risk factors are discussed.